Remote indicating control circuit



March 20, 1962 R. w. BROWN INVEN TOR.

RICHARD W. BROWN W/Wm ATTORNEY 3,026,448 REMQTE HQDTQATTNG CONTRQL CIRSUIT Richard W. Brown, Meadville, Minn, assignor to Minneapoiis-Hcneywell Regulator Company, Minneapolis, Minn, a corporation of Delaware Filed June 30, 1960, Ser. No. 39,947 Claims. (U. 315-435) The present invention is directed to a remote indicating electrical circuit capable of providing control of a remote device while simultaneously providing energization for a local indicating light. More specifically, the present invention is directed to an indicator light for a low voltage control system particularly adaptable for control of lighting equipment by means of two wires, as opposed to the more common three-wire systems.

In the low voltage lighting control field there are two basic types of control systems. One system utilizes a push button or momentary type switch that operates to control a stepping relay. The stepping relay in turn supplies the line voltage to the lighting load and subsequently removes the line voltage from the lighting load. With a two-wire system using a momentary type push button, the condition of the remote lighting load is unknown at any time unless the lighting load is within visual contact of the person controlling the switch. This is generally the case, but there are many situations where a remote lighting load is controlled by a push-button, two-wire system. in this type of system, extensive and costly remote indicating lights using two extra wires are available that operate off auxiliary contacts at the remote position. The auxiliary contacts complete a circuit back to the switch which controls the lighting load and thereby provides an indication of the condition of the system. This arrangement requires extra wiring and additional equipment that is rather expensive.

In order to overcome the need of four wires for remote indication, some manufacturers have gone to a three-wire system utilizing a two-position momentary switch. In the conventional three-wire system a common wire is utilized with each of the two other wires to provide a definite on or a definite off position. When it is desired to turn the light off, it is necessary only to throw the switch to the appropriate position, and the light will either remain in the off position or will be turned off. These types of systems are well known in the low voltage wiring control art and their deficiencies have been long recognized.

The present invention is directed to a two-wire, momentary switch arrangement that still provides the necessary indicator light at the switch to indicate the condition of the remote load. The present arrangement is exceedingly simple and requires very little in the way of additional equipment beyond that which is needed in the basic control system.

It is the object, therefore, of the present arrangement to provide a two-wire, low voltage control circuit with a remote indicator light.

A further object of the present invention is to supply a simplified indicating light circuit to enable the economical use of two-wire control with a momentary type of switch in such applications as low voltage lighting control systems.

Yet a further object of the present invention is to provide an unusual relay control system with a remote indicating light to show the position of the relay.

Still a further object of the present invention is to provide a simplified low voltage control system with a remote indicator light that requires no additional intermediate wiring between the switch and the controlled In order to overcome the deficiencies 3,32%,448 Patented Mar. 20, 1362 ice unit and further requires only the addition of minor circuit elements.

These and other objects will become apparent when the highly simplified circuit diagram of the low voltage control system is explained in connection with the accompanying drawing.

The present disclosure is a highly simplified schematic arrangement that might readily be used in a residential low voltage wiring control system. As such conductors 1t) and 11 represent 115 volt alternating current at 60 cycles, of the type normally supplied in residential and commercial applications. Connected to conductors in and 11 are conductors 12 and 13 which energize the primary 14 of a transformer generally shown at 15. The transformer 15 has a secondary winding 16 that supplies 24 volts of alternating current. The transformer 15 is of a conventional design utilized in control circuits for lighting control, control of furnaces, air conditioning equipment, and many other household control functions.

The secondary 16 is connected by means of conductor 17 to an indicator light 20 and a momentary type switch 21. The momentary switch 21 is of any conventional design and can be considered similar to a pushbutton switch that makes contact upon application of pressure and breaks contact upon removal of application of pressure. The switch 21 is connected by conductors 22 and 24 to an asymmetrical conducting means 23 in the form of a diode or rectifier. It will be noted that the indicator light 2% and the rectifier 23 are in series and form a parallel combination with the switch 21. The parallel combination is connected by conductor 25 to a second asymmetrical conducting means or rectifier 26, and is in series circuit with an alternate action means 27, which is in the form of a stepping relay. The stepping relay 27 can be of any conventional design such as an armature operated by electro-magnetic means that in turn operates a rotating member that is engaged by a pawl and ratchet. The design of an alternate action means or relay of the type described is quite common and will not be gone into in more detail at present. This type of relay is shown, for example, in US. Patent 2,348,432.

The relay 27 is connected by conductor 30 back to the secondary 16 of transformer 15. The relay 27 has an armature 31 (schematically represented) that operates current control means. The current control means in the present case are a pair of switches 32 and 33. Both of the switches 32 and 33 are opened at the same time and subsequently closed together upon operation of the relay 27; The switch 32 is connected by conductor 34 to alternately short circuit the rectifier 26. The purpose of this short circuit will be explained when the operation of this circuit is described.

The switch 33 is connected from conductor 10, by means of conductor 35, to a common conductor 36 that supplies current to load means generally shown at 40 in the form of two electric light bulbs 41 and 42. The current through the bulbs 41 and 42 is returned by conductors 43 and 44 to conductor 11 to complete an electric circuit through the bulbs 41 and 42 whenever switch 33 is closed.

Operation The operation of the present circuit is based on being able to operate the relay 27 either on full power or on a half-wave basis as controlled by the rectifiers 23 and 26. In the circuit as shown, the switch 21 is open as are switches 32 and 33. In this condition the indicator light 2i) is oil, as well as there being no power to energize lights 41 and 42. If the switch 21 is momentarily closed, the indicator light 20 and the rectifier 23 are short circuited. Now the secondary 16 of transsecondary 16 and the relay 27.

wire low voltage'wiring, control systems.

. 3 a former 1.5 is directly across the combination of the relay 27 and the rectifier 26. This allows the relay 27 to pull in as the unit is designed to operate on halfcycles of DC. as well ason full A.C. power. As soon as relay 27 pulls in, the switch 32 shorts out diode 26 and closes switch 33, turning on the lights 41 and 42. As long as the momentary switch 21 is held down, this condition remains fixed.

As soon as the momentary switch 21- is released, thereby completing the energizing operation, the short is removed from the series combination of indicator light 2% and the diode23. By removing the short and inserting the series connected lamp 2% and rectifier 23, a continuous series circuit is established between the transformer Since the diode 2d is shorted out, the relay 27 continues to operate on halfwave rectification through the diode 23 and the indicator light 20. The indicator light is selected so that the current being drawn is sufficient to give an indication that the circuit has been closed. The indicator light also has sufficient impedance soas not to form a permanent short circuit across the switch 21. The cur-rent drawn through the lamp 20 is of a small enough magnitude to allow the relay 27 to resetv itselfbut since it is an alternate action type or ratchet type relay, the contacts 32 and 33 do not move.

Upon subsequent energizationof switch 21, the impedance of the light 26 is. shortcircuited, thereby causing the'stepping relay 2? to operate a second time. The operation of the stepping relay opens switches 32 and 33, thereby extinguishing lights 41 and 42. The subsequent release of the momentary switch 21 places the rectifier 23 back intothe circuit thereby being in a back-to-back relationship or in opposition to the rectifier 26. This eliminates all current flow through the relay 2'7 and the relay again resets in preparation for operation to turn on the lights 41 and 4 2' upon the demand by placing the switch. 21 into contact once again.

It: can thus be seen that the present arrangement provides for a unique remote indicating controlcircuit for an alternating current system. The present arrangement is-very distinctly advantageous over other systems'as the I,

only components which are added to the conventional two-wire system are a pair of diodes, and extra con-tact to arelaywhich must exist in this system'anyway, and an indicating bulb. All of these components are very' inexpensive due to their small physical size and low current drains. The present system, therefore, fills a need not previously satisfied by the existing two-wire and three- Due to the nature of the present arrangement, many modifications arepossible in the'-wiring and it istherefore the intent of the applicant'to disclose only one of the many preferred embodiments. As such; the applicant wishes to be limited in the scope of his invention only to'the' appended claims.

7 I claim as my invention:

1. .A remote indicating control circuit having; alternating current voltage supply means; asymmetrical conducting means connected in series circuit with indicator means for limiting current flow through said indicator means to alternate half-cycles of" said alternating current voltage means; switch means connected in parallel circuit with said asymmetrical conducting means and said indicator means; second asymmetrical conducting means and alternate action control means connected in series circuit with said voltage supply means and said parallelcircuinsaid firstand second asymmetrical conducting means being connectedin opposition to each other;.and current control-means operated bysaid alternate action means to short said second asymmetrical means out of the circuit and concurrentlyoperate load means.

2. A remote indicating control circuit for low voltage lighting having an alternating current voltage supply;

asymmetrical conducting means connected in series circuit with indicator means for limiting current flow through said indicator means to alternate half-cycles of said alternating current voltage; switch means connected in parallel circuit with said asymmetrical conducting means and said indicator means; second asymmetrical conducting means conducting means being shorted out to indicate the po-' sition of said alternate action means.

3. A remote indicating control circuit having an alternating current voltage supply means; a diode connected in series circuit with an indicator lamp for limiting current flow through said lamp to alternate half-cycles of said alternating current voltage means; momentary switch means connected in parallel circuit with said diode and said lamp; a second diode and a stepping relay connected in series circuit with said voltage supply means and said parallel circuit; said first and second diodes being connected in opposition to each other; and contacts operated by said relay to short said second diode out of the circuit and concurrently operate load means.

4; A remote indicating control circuit for low voltage lighting having an alternating current voltage supply; a diode connected in series circuit with an indicator lamp for limiting current flow through said lamp to alternate half-cycles of said alternating current voltage; a momentary switch connected in parallel circuit'with said diode and said lamp; a second diode and alternate action co-ntrolmeans connected in series circuit with said voltage supply and said parallel circuit; said first and second diodes being connected in opposition to each other; and contacts operated by said alternate action means to short said second diode out of the circuit and concurrently operate load means; said indicator lamp being energized by-said second diode being shorted out to indicate the po sition of said alternate action means.

5. A remote indicating control circuit for low voltage lighting having an alternating current voltage supply; a diode connected in series circuit with an indicator lamp for limiting current flow through said lamp to" alternate half-cycles of said alternating current voltage; a monien ta'ry switch connected in parallel circuit withsaid diode and said lamp;a second diode and a stepping relay connect'ed in series circuit with said voltage supply and said parallel circuit; said first and second diodes'being connected in opposition to each other; and" contacts operated by said relay to'sh'oi't said second diode out of the circuit and concurrently operate a lighting load; said iiidicator lamp being energized by said second diode being shorted out to indicate the position of said contacts.

References Cited i'n the fileof'this patent UNITED STATES PATENTS 

